Encased electrical instrument



April 1959 E. M. EADIE, JR., ETTAL 1 2,883,489

ENCASED ELECTRICAL INSTRUMENT Filed Dec. 6. 1954 2/ 22 z/ /4' I W;- Z/b g l4 3 9 a 23 25 l Fg. I

INVENTORS Eowanp M. E4 on; JR. ROBERT L. SHALLCROSS ATTORNEY United States Patent ENCASED ELECTRICAL INSTRUMENT Edward M. Eadie, Jr., Westfield, and Robert L. Shallcross, Clark Township, Union County, NJ., assignors, by mesne assignments, to Daystrom, Incorporated, Murray Hill, N.J., a corporation of New Jersey Application December 6, 1954, Serial No. 473,288

3 Claims. (Cl. 200-110) This invention relates to encased electrical instruments and more particularly to the mechanical support of the instrument within its case.

An object of this invention is the provision of an electrical instrument having structural features affording certain manufacturing and assembly economies.

An object of this invention is the provision of an electrical measuring instrument or instrument type relay in which the entire mechanism is supported on an insulating material plate or deck which, in turn, is mounted on flanges or ribs rigidly secured to the enclosing housing or case.

An object of this invention is the provision of an instrument relay comprising a metal, cup-like case having ribs therein, an apertured deck of insulating material removably secured to said ribs, a permanent magnetmovable coil mechanism supported by the deck and including a staff extending through the aperture of the deck, and a movable contact secured to the staff and cooperating with a pair of spaced stationary contacts.

A further object of this invention is to provide a relay of the type stated in which the insulating material deck serves as the printed scale plate and has the stationary relay contacts mounted thereon.

These and other objects and the advantages of the invention will be apparent from the following specification when taken with the accompanying drawings. It will be understood the drawings are for purposes of illustration and are not to be construed as defining the scope or limits of the invention, reference being had for the latter purpose to the claims appended hereto.

In the drawings wherein like reference characters denote like parts in the several views:

Figure 1 is a plan view of an encased electrical instrument, specifically an instrument type electrical relay, embodying the invention;

Figure 2 is a side elevation of the encased instrument with parts in section on the planes indicated by line 2-2 of Figure 1;

Figure 3 is a perspective view of the insulating material deck as seen from above the same;

Figure 4 is a bottom plan view of the deck;

Figure 5 is a fragmentary sectional view on the plane of line 5-5 of Figure 1;

Figure 6 is a perspective view of one of the brackets for supporting a stationary contact; and

Figure 7 is a top plan view on a smaller scale of the empty instrument case.

In the drawings, the reference numeral 1 identifies a cylindrical sheet steel case of cup shape having a radial flange 1' at its outer end which is provided with bushings 2 upon which a transparent plastic window 3 is fitted and secured by screws 4 passing through a metal rim 5.

The illustrated instrument is a relay of a magnetized core type and includes a movable system comprising a coil 6 disposed about its magnetized core and carrying a pointer or contact arm 7 and journalled by staffs 8, 8' in bearings 9, 9' mounted in bridges 10, 10' supported "Ice from the annular soft iron yoke 11 by posts 12, 12', respectively. The permanent magnet core is spaced from the inner surface of the yoke which defines an axial receiving hole.

In accordance with the invention, the upper end of the yoke 11 is seated against the lower face of an inwardly projecting annular flange which defines a ledge 13 and a circular opening 13' in a preferably circular plate or mounting deck 14 of insulating material. The opening 13' is laterally offset from the center of the plate 14, thereby leaving enough room for screw contact brackets, to be described. The yoke 11, and thereby the entire relay, is secured to the mounting deck 14 by the reduced diameter lower ends of the upper posts 12 which extend through oppositely arranged radial slots 15. The deck 14 rests upon transversely extending surfaces of opposed coplanar segmental ribs 16 which are secured to the inner face of, and project laterally into the interior of the shielding case 1 by weld metal 17, and is anchored to the ribs by screws 18 which extend through openings 19 of the deck, while it spans the space therebetween.

Recesses 20 are molded or otherwise provided in the upper face of the deck 14 to receive the lower arms of angle brackets 21 into which the stationary screw contacts 22 are threaded. The screws 23 which anchor the brackets 21 in the correspondingly shaped recesses of deck 14 also clamp soldering terminals 24 for these contacts to the lower face of the deck. The brackets 21 are of resilient metal with the upturned end of each provided with a slot 21a through the threaded contactreceiving bore 21b, as shown in Figure 6; the slot being squeezed together slightly to hold the associated contact 22 frictionally against inadvertent tuming movement or loosening.

All electrical connections to the moving coil and the contacts of the relay are made within the case 1 desirably soldered to the inner ends of terminals 25, usually five in number, which are insulated from and supported by a known type of terminal header 26 which is secured in and seals an opening 26a in the lower end of case 1.

The upper surface of the deck 14 is covered with a White enamel coating and has a scale 27 printed thereon, as well as other identifying data 28 including, for example, a model number and the manufacturers name and trade-mark, not shown. The upper staff 8 extends through the opening 13 of deck 14 and the contact arm 7 extends between the stationary contacts 22 and overlies the scale 27.

It is to be understood that the invention is not limited to the particular type of instrument or relay herein shown and described since instruments with the more conventional type of C-shaped permanent magnet and soft iron core may be supported in a case by an insulating material deck which also serves as the scale plate of the instrument. 1

From the foregoing description it will be apparent that the entire instrument mechanism is supported by the insulator deck 14. Such sub-assembly affords a maximum facility for making necessary adjustments, tests and inspection before the instrument is placed into the case. Similarly, the entire mechanism may be removed for repair, when required, by simply removing the two screws 18 that are screwed into appropriate threaded holes in the supporting ribs 16.

Having now described our invention in accordance with the requirements of the Patent Statutes what we desire to protect by Letters Patent of the United States is set forth in the following claims.

We claim:

1. An instrument relay comprising a cup-shaped metal case with cylindrical side walls, a pair of coplanar segmental ribs, one connected to the inside of each side of said caseand projecting toward one another, the adjacent straight sides thereof defining a space therebetween, a circular deck of insulating material spanning said space and secured to said ribs, said deck having a recess in its upper face to receive the lower arm of an angular bracket and a circular opening therethrough laterally ofiset with V respect to the center of said deck so as to clear said extending through oppositely-arranged radial slots in said flange and clamping said yoke thereto, alined bearings carried by the upper and lower bridges, a coil rotatable in said bearings, 21 contact secured to the coil and movable over the upper surface of said deck, an L-shaped bracket having a lower arm disposed within said recess 4 in the upper surface of the deck, and a threaded contact screw carried by the bracket and adapted to be engaged by the movable contact.

2. The invention as recited in claim 1, wherein the said bracket is secured to the deck by a screw passing through the deck and into a threaded hole in the lower arm of the bracket, and including a soldering terminal secured to the deck by the said screw.

3. The invention as recited in claim 2, including connection terminals passing through the bottom of the metal case, and lead wires soldered to the inner ends of said terminals for conducting current to the movable coil, the movable contact and the bracket.

References Cited in the file of this patent UNITED STATES PATENTS 1,521,032 MacGahan Dec. 30, 1924 1,782,454 Arnold Nov. 25, 1930 1,901,197 Simpson Mar. 14, 1933 1,927,346 Lawrence Sept, 19, 1933 1,963,283 Triplett June 19, 1934 2,422,714 Bigelow June 24, 1947 

